Fluid Structure Interaction for patient specific risk assessment in abdominal aortic aneurysms

Rupture of abdominal aortic aneurysm (AAA) ranks as the 13th leading cause of death in the US. Fluid Structure Interaction (FSI) analysis was conducted with the aim of strengthening the current diagnostic measures of the disease, in particular, to (i) predict the location of wall rupture, (ii) estimate the state of pathology from the calculated ruptured potential index (RPI) and (iii) predict the disease progression by comparing healthy and pathological aortas (non-ruptured and ruptured AAAs). FSI simulations were carried out on three dimensional patient specific geometries reconstructed from CT data. The arterial wall in the reconstructed geometries was modeled as anisotropic material. Other critical characteristics of AAA such as intra-luminal thrombus (ILT) and embedded calcifications (Ca) were incorporated in the patient-specific models. Results obtained from the FSI simulations indicate an increase in wall shear stress with progression of the disease. ILT is found to reduce the wall stress while calcium deposition on walls increases the local wall stress. Using rupture potential index (RPI), the location of rupture is successfully predicted.